2017 Atlantic hurricane season (Downcasted version)
The 2017 Atlantic hurricane season was above average in terms of named storms, but well below average in terms of hurricanes. It featured no major hurricanes, for the first time since 2013. 15 tropical cyclones formed, 14 of which became named storms, 2 of which became hurricanes. No hurricanes exceeded category 1 intensity. Seasonal forecasts Ahead of and during the season, several national meteorological services and scientific agencies forecast how many named storms, hurricanes and major (Category 3 or higher on the Saffir–Simpson scale) hurricanes will form during a season and/or how many tropical cyclones will affect a particular country. These agencies include the Tropical Storm Risk (TSR) Consortium of the University College London, the National Oceanic and Atmospheric Administration (NOAA) and Colorado State University (CSU). The forecasts include weekly and monthly changes in significant factors that help determine the number of tropical storms, hurricanes, and major hurricanes within a particular year. Some of these forecasts also take into consideration what happened in previous seasons and the dissipation of the 2014–16 El Niño event. On average, an Atlantic hurricane season between 1981 and 2010 contained twelve tropical storms, six hurricanes, and two major hurricanes, with an Accumulated Cyclone Energy (ACE) index of between 66 and 103 units. Pre-season outlooks The first forecast for the year was issued by TSR on December 13, 2016. They anticipated that the 2017 season would be a near-average season, with a prediction of 14 named storms, 6 hurricanes, and 3 major hurricanes. They also predicted an ACE index of around 101 units. On December 14, CSU released a qualitative discussion detailing five possible scenarios for the 2017 season, taking into account the state of the Atlantic Multidecadal Oscillation and the possibility of El Niño developing during the season. TSR lowered their forecast numbers on April 5, 2017 to 11 named storms, 4 hurricanes, and 2 major hurricanes, based on recent trends favoring the development of El Niño. The next day, CSU released their prediction, also predicting a total of 11 named storms, 4 hurricanes, and 2 major hurricanes. On April 17, The Weather Company released their forecasts, calling for 2017 to be a near-average season, with a total of 12 named storms, 6 hurricanes, and 2 major hurricanes. The next day, on April 18, North Carolina State University released their prediction, also predicting a near-average season, with a total of 11–15 named storms, 4–6 hurricanes, and 1–3 major hurricanes. On May 20, The Weather Company issued an updated forecast, raising their numbers to 14 named storms, 7 hurricanes, and 3 major hurricanes to account for Tropical Storm Arlene as well as the decreasing chance of El Niño forming during the season. On May 25, NOAA released their prediction, citing a 70% chance of an above average season due to "a weak or nonexistent El Niño", calling for 11–17 named storms, 5–9 hurricanes, and 2–4 major hurricanes. On May 26, TSR updated its prediction to around the same numbers as its December 2016 prediction, with only a minor change in the expected ACE index amount to 98 units. Mid-season outlooks CSU updated their forecast on June 1 to include 14 named storms, 6 hurricanes and 2 major hurricanes to include Tropical Storm Arlene. It was based on the current status of the North Atlantic Oscillation, which was showing signs of leaning towards a negative phase, favoring a warmer tropical Atlantic; and the chances of El Niño forming were significantly lower. However, they stressed on the uncertainty that the El Niño–Southern Oscillation could be in a warm-neutral phase or weak El Niño conditions by the peak of the season. On the same day, the United Kingdom Met Office (UKMO) released its forecast of a very slightly above-average season. It predicted 13 named storms with a 70% chance that the number would be in the range 10 to 16 and 8 hurricanes with a 70% chance that the number would be in the range 6 to 10. It also predicted an ACE index of 145 with a 70% chance that the index would be between 92 and 198.On July 4, TSR released their fourth forecast for the season, increasing their predicted numbers to 17 named storms, 7 hurricanes, and 3 major hurricanes, due to the fact that El Niño conditions would no longer develop by the peak of the season and the warming of sea-surface temperatures across the basin. Additionally, they predicted a revised ACE index of 116 units. Storms Tropical Storm Arlene Tropical Storm Bret Tropical Storm Cindy Tropical Depression Four Tropical Storm Don Tropical Storm Emily Tropical Storm Franklin Tropical Storm Gert Hurricane Harvey Hurricane Irma Tropical Storm Jose Tropical Storm Katia Tropical Storm Lee Tropical Storm Maria Unnamed Subtropical Storm Category:Funny seasons